The EWS-FLI transcription factor present in vast variety of Ewing's sarcoma family of tumors (ESFT) was characterized over ten years ago. Progress in the treatment of Ewing's sarcoma the second most common bone tumor in children and adolescents, has improved survival for patients with localized tumors. However, patients with metastases still fare badly and the therapy carries short and long-term toxicities. The Ewing sarcoma family of tumors (ESFT) is characterized by a chromosomal translocation that generates EWS-FLI1, on oncogenic fusion transcription factor whose continued expression is believed to be critical for ESFT cell survival (Balamuth, N J, Womer, R B., Lancet Oncology 11, 184-192 (2010)). ETS transcription factors, such as FLI1 and SPIB, are recurrently deregulated in human lymphomas (Bonetti et al, Blood 2013; Lenz et al, PNAS 2008). The small molecule YK-4-279 inhibits binding of EWS1-FLI1 fusion protein to RHA resulting in growth arrest and apoptosis in Ewing sarcoma cells (Erkizan et al, Nat Med 2009) and it was previously showed that YK-4-279 has in vitro anti-lymphoma activity (Chung et al, AACR 2015).
In vitro and in vivo studies have demonstrated that the inhibition of the binding of the oncoprotein, EWS-FLI1, to RNA Helicase A (RHA) leads to a decrease in proliferation of ESFT cell lines and a decrease of tumor volume. EWS-FLI1 lacks enzymatic activity, however, the protein-protein interaction between RNA helicase A (RHA) and EWS-FLI1-modulates oncogenesis, and is therefore required for the maintenance of the tumor growth (Hyariye N Erkizan et al. Nature Medicine 15(7) 750-756 (2009)). The paradigm of disrupting key protein interactions may have utility in treatment of diseases including sarcomas with similar translocations, and leukemias with MLL translocations ((Helman L J, Meltzer P. Mechanisms of sarcoma development. Nat Rev Cancer 2003; 3(9):685-94); and Pui C H, et al., N Engl J Med 2004; 350(15):1535-48). Moreover, disordered proteins may be excellent therapeutic targets based on their intrinsic biochemical properties (Cheng Y, LeGall T, Oldfield C J, et al., Trends Biotechnol 2006; 24(10):435-42).